User manual

ILX34-AENWG ♦ Point I/O Platform Reference
Wireless POINT I/O Adapter User Manual

ProSoftTechnology,Inc. Page189of209
September19,2011

6.5.5 Collinear array antennas

Acollineararrayantennaistypicallycomposedofseverallinearantennasstackedontopofeach
other.Themorestackedelementsithas,thelongeritis,andthemoregainithas.Itisfedinon
oneend.
Theantennapatternistorroidal.Itsazimuthalbeamwidthis360°
(omnidirectional).Itsvertical
beamwidthdependsonthenumberofelements/length,wheremoreelementsequalnarrower
beamwidth.Theantennagainalsodependsonthenumberofelements/length,wheremore
elementsproducehighergain.Typicalgainis5to10dBi.
Theantennapolarityislinear,orparalleltothelengthofthe
antenna.

6.5.6 Yagi Array Antenna
Ayagiantennaiscomposedofanarrayoflinearelements,eachparalleltooneanotherand
attachedperpendiculartoandalongthelengthofametalboom.Thefeedisattachedtoonly
oneoftheelements.Elementsononesideofthefedelementarelongerandactas
reflectors;
elementsontheothersideareshorterandactasdirectors.Thiscausestheantennatoradiatein
abeamoutoftheendwiththeshorterelements.Thepatterndependsontheoverallgeometry,
includingthenumberofelements,elementspacing,elementlength,andsoon.Sometimesthe
antennaisenclosedinaprotectivetubehidingtheactualantennageometry.
Theantennapattern(page187)isabeampointedalongtheboomtowardtheendwiththe
shorterelements.Thebeamwidthvarieswithantennageometrybutgenerallyisproportionalto
thelength(wherelongerlengthproducesanarrowerbeam).

Theantennagain(page188)varieswithantennageometrybutgenerallyisproportionaltothe
length(wherelongerlengthproduceshighergain).Typicalvaluesare6to15dBi.
TheantennapolarityisLinear(paralleltotheelements,perpendiculartotheboom).

RefertotheAntennaTypesoverviewsectionforothertypesofapprovedantennas.